Lee Epstein and Jeffrey Segal have an interesting op ed in the Washington Post on how justices change their views over time. Here is excerpt:

So, yes, Samuel Alito, in all likelihood, will be a conservative justice and will reach decisions in accord with that label. But there's a "but" -- actually several, all recent or current justices: David Souter, Harry Blackmun, John Paul Stevens, Anthony Kennedy and Sandra Day O'Connor, to name five justices for whom, to greater or lesser extent, ideological labels proved misleading. The "but" offers important insights into why some nominees, once they become justices, sometimes don't behave as predicted and how the court's dynamics can affect their views.

Then there's O'Connor, the swing justice during her last few terms on the court. Over time, this moderate-to-conservative Reagan appointee grew more liberal -- and with that movement came a change in her voting behavior. So, based on our calculations, the odds of the court upholding an affirmative action program just 10 years ago were no more than one out of three; but by the time the court heard a challenge to the University of Michigan law school's affirmative action plan in its 2002 term, the odds had increased to more than 50 percent -- largely because of O'Connor's move to the left. In the end, O'Connor did provide the key vote to uphold the law school's program (while also joining the 6-3 majority in striking down a different affirmative action plan governing Michigan's undergraduate admissions).

The piece concludes:

Where does this leave us with Judge, likely-to-be Justice, Alito? History provides little reason to question predictions that Alito will cast right-of-center votes, and reliably right-of-center votes at that. On the other hand, if that same history is any indication, even his thick judicial record may provide less insight into his future votes than we might imagine.

All this strikes me as another argument for Supreme Court term limits. That judges' views can change or operate in unpredictable ways over time is a reason to limit the length of time that they can serve on the Court. Except for introducing uncertainty and a peculiar kind of pluralism, there is little benefit to allowing them to serve long enough to modify their views.